Two sets of capacitor load based I-V curve tracer for photovoltaic cell

Two sets of capacitor load based /-V curve tracer for photovoltaic cell are designed and implemented (Test system one includes Raspberry Pi, capacitor, current sensor, and analog-to-digital converter, etc.; test system two includes data acquisition card, capacitor, and sampling resistor, etc.). The conclusions are made: (1) the measurement results of both systems are generally correct, but neither can obtain short-circuit current due to the inability to achieve a load resistance of zero. Test system two based on the data acquisition card is found to be higher accuracy. (2) The factors affecting the accuracy of test system two is studied. The larger capacitance leads to more precise measured data. Smaller sampling resistors result in output voltages closer to zero and more complete /-V curves. When the sampling rate is high, noise may cause oscillating /-V curve.